Shale retorting process



Filed Dec. 26, 1956 M a J Iran/570a 7! United States Patent Office 3,004,898 Patented Oct. 17, 1961 3,004,898 SHALE RETORTING PROCESS Roland F. De ering, Whittier, Calif., assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of'California Filed Dec. 26, 1956, Ser. No. 630,577 15 Claims. (Cl. 202-46) This invention relates generally to a process for solidsfiuid contacting and it particularly relates to the heat treating of oil-containing or oil-producingsolids to produce hydrocarbon oils and gases therefrom. The invention particularly is well adapted to the retorting of oil shale to produce shale oil and gas.

Some processes for the eduction of shale oils and gases involvethe downward passage of shale rock as a moving bed by gravity through a vertical heat treating kiln. During this passage the rock is heated to eduction temperatures by direct or indirect means. From a thermal efficiency standpoint the direct heating means is preferred in which a countercurrent contact of hot gases with the shale rock is employed. To avoid the large fuel consumption otherwise required, most of these processes involve the direct injection of air or other oxygen-containinggas into the bottom of the kiln to burn the carbonaceous residue from the spent shale. This generates hot flue gases needed to heat the rock. However, some difliculties are encountered with the fusion of the spent shale due to this burning and frequently the fused or partially fused rock plugs the air inlet requiring a shutdown. Since all of the hydrocarbon product is removed at the top of the kiln, in most processes it must be removed as a vapor and this requires extensive cooling and condensing facilities. Much oil shale is found in areas where cooling water is extremely scarce which makes these processes unfeasible. In the other processes the oil is condensed on the shale forming a mist and is carried out by'the gas stream. However this also causes frequent operating difliculties because of agglomeration and runback of the oil into the kiln where it is decomposed or otherwise lost.

Other shale eduction processes have successfully avoided the large fuel and condensing water requirements and the difliculties resulting from refluxing or runback of oil by utilizing an upfiow of shale rock and a downflow of heating gas. The shale is fed upwardly in sequence through a perforated disengaging section and a heat treating or kiln section. Air or other oxygen-containing gas enters the top and moves downwardly through the'heat treating section, is first preheated in cooling the hot shale ash at the top, burns the carbonaceous residue from the spent shale at a lower level, and the hot flue gases continue downwardly to still lower levels where they heat the shale rock and educt hydrocarbon oils and gases. The whole vapor phase passes downwardly in direct contact with the raw shale, and is cooled thereby condensing the hydrocarbon oil and preheating the raw shale near the bottom of the kiln section. The liquid and gaseous products are drawn oif at the disengaging section and are thus separated from the upwardly moving shale rock. A solids feeder passes the shale rock upwardly through the disengaging and heat treating sections and displaces the shale ash out the top of the unit. The process supplies its own fuel in the form of carbonaceous spent shale. It cools and partially condenses its own product in preheating the raw shale rock.

Several problems however are involved in the latter upfiow solids process which are occasoinally troublesome. Because the process derives its heat from the burning of a solid hydrocarbonaceous residue on the educted or retorted solids by contacting it with an oxygen-containing gas, the burning temperatures are necessarily of the order of 2000 F. to 2500 F. inside the apparatus to maintain oxide because of the high temperatures of carbon combustion. These high temperatures also result in'incipient fusion of the shale ash causing the formation of clinkers or partially sintered agglomerates which adversely eflect the upfiow of solids as well as the downflow of gas through the retort. One way of solving these problems is to employ some means for agitating the burning solids so as to prevent formation of these agglomerates or break up those which do form. In the past this agitation has been accomplished by plows which rotate slowly through the top of the upwardly moving solids bed. Because of the high temperatures and the high stresses involved, these plows require large quantities of power to move them, are necessarily constructed of alloy steel with rather elaborate supporting and rotating structures, and must be cooled to prevent high temperature failure. An additional problem involves the prmence of oxygen in the system to support the combustion of the carbonaceous residue on the spent shale. Unavoidably a part of this oxygen reacts with the educted materials to form partially oxygenated or partially oxidized materials which apparently render the liquid portion of the product rather unstable.

Further, the previous processes have been troubled to various extents by the presence of shale fines-that is, small solid particles of about 0.5 inch or below, in the feed. Some of the processes fractionate the feed to separate these fines and discard them. This obviously may constitute a serious economic loss since in some cases crushing the raw shale feed, can produce as much as 20% or more of such fines. Other processes are more amenable to treating the larger particles in the presence of the fines. It has been discovered however that even in these processes the presence of the fines tends to increase the pressure differential generated by fluids flowing through the shale bed and sometimes concentrations of the fines will build up causing fluid channeling and nonuniform treatment of the shale.

The present invention successfully overcomes these and other problems and provides a new retorting process that achieves high oil recovery at substantially higher retorting rates, permits accurate control of retorting temperatures which are substantially reduced over those wherein the spent shale is burned with oxygen, minimizes degradation of the liquid product, produces an oil product of substantially increased stability, and simultaneously processes shale fines at high retorting efliciency.

It is. therefore a primary object of this invention to provide a new process for the separation or production of hydrocarbon gases and liquids from oil-containing or oilproducing solids such as oil shale. V

A more particular object is to provide a process in which the oil shale is passed upwardly through aretorting zone countercurrent to a flow of hot eduction gas produced by the combustion of part of the product gas so as to eliminate any substantial quantities of oxygen therefrom and provide a substantially inert heating medium.

It is a further object of this invention to provide a shale retorting process of the type indicated in which the maximum retort temperatures are of the order of 1000" F. below those characteristic of the spent shale combustion processes.

It is an additional object of this invention to separate solids fines having a mesh size of less than about onehalf inch from the raw shale feed and contact these fines with the recirculated hot eduction gases prior to entrance r 3 of these gases into contact with the larger sized shale particles passing upwardly through the main retort.

It is a more specific object of this invention to produce oil and gas from oil shale by low temperature rero ing including the steps of burning one portion of the gas product under controlled conditions with air in .a burning zene extern l to the retort rep oduce a hot reyc as, ntrod cin th gas into a mixture wit a second portion of the hydrocarbon-containing gas to produce a c oler cduetion ga passing his gas first int concurrent con act with the shale fines to retort them and then into countercurrent contact with the fines-free shale to produce a shale gas and vapor product, and

paniallv c nd n ing the gas an po a ai s fresh 001 fines-free oil shale.

Other objects and advantages of this invention will become apparent to those skilled in the art as the description and illustration thereof proceed.

The improved process of this invention will be more readily understood by reference to the accompanying drawing and the description thereof in which is shown a schematic process flow diagram of the present invention in which shale fines and the larger shale solids areseparated from one another and are separately and simultaneously treated at relatively low temperatures in sequence to obtain the maximum possible production of the desired product.

Referring now more particularly to the drawing, the process of the present invention will be described in terms of a specific example of the present invention as applied to the retorting of crushed Colorado oil shale of to 6 inches in average size and at a rate of 700 tons per day to produce shale oil and shale gas; The apparatus of the present invention for treating the larger shale particles consists essentially of three parts; namely, an upper heat treating or eduction kiln 10 about 14 feet high and averaging feet in diameter, an intermediate perforate disengaging section 12 about 11 feet high and having upper and lower diameters of about 13 feet and 5.5 feet *respectively, and a lower reciprocating piston shale feeder contained within feeder housing 14.

Shale feeder housing 14 contains a vertically reciprocating feeder piston about 5.5 feet in diameter which is contained within an oscillating feeder cylinder, not shown. The feeder cylinder oscillates in a vertical plane between a vertical feeding position, in which it is aligned with the vertical axis of kiln 10 and disengaging zone 12,

and an inclined feeder charging position in which the feeder cylinder is inclined from the vertical and aligned with the lower outlet opening of shale feed hopper 16.

The feeder piston and the feeder cylinder are separately oscillated hydraulically so that raw shale freed of fines fisdrawn into the feeder cylinder from feeder hopper 16,

the feeder cylinder oscillates into the vertical position,

the feeder piston forces the charge of fresh shale upwardly into disengaging zone 12 and kiln 10 displacing solids above it upwardly and displacing spent shale from the top, and then the feeder Cylinder oscillates into the inclined position to accept a new shale charge completing the feeder cycle. In this way the larger fines-free shale is passed upwardly through the retort countercurrent to the hot eduction gases subsequently described.

The raw shale feed is introduced at a rate of about 700 tons per day through line 18 into shale separation zone 29. The shale is Colorado oil shale crushed so as to have substantially no pieces larger than'6 inches mesh size. The shale has a FischerAssay of 28.0 gallons per ton. through line 22 at a rate of about 140 tons per day, constituting about of the total shale feed. This stream comprises the shale particles which pass a 0.5 inch mesh. The remaining 80%, or about 560 tons per day, is passed through line 24 into shale hopper 16 from which it is fed, as previously described, upwardly through the retort. The shale fines flow into a rotary air A shale fines stream is removed from zone 20 4 lock 26 where they are introduced into a special fines retort 28 subsequently described.

Surrounding the perforated disengaging zone 12 is a jacket 30 which constitutes a collection manifold for the product oils and gases. During the retorting in kiln 10 the fines-free shale is gradually heated to temperatures somewhat in excess of 5.00 F. The organic matter, commonly termed kerogen, decomposes at these temperatures to produce shale oil gases and vapors. These move downwardly-in the reduction gas flow and are cooled and condensed in direct contact with the upwardly moving cold-fresh shale. The cooled gases and condensed vapors collect in manifold 30 horn which they are withdrawn.

The liquid portion of the product is removed therefrom through line 32 and. is introduced into product fines separator 34. Here the liquid oil is allowed to settle for periods ranging from about 0.5 to about 2 hours. A thickened slurry of fines in oil is removed from separator 34 through line 36 andis pumped by means of pump .38 at a rate controlled by valve 40 through sludge recycle line 42 to sludge separator 44. v

Simultaneously a fines slurry is pumped from feeder housing 14 through lines 46 and 48 by means of pump 50 at .a rate controlled byvalve 52. This slurry is also conveyed through line .42 intosludge separator 44. The thickened sludge consisting of shale fines and a small mount of oil isintroduced through line 54 into the top of kiln 10. The separated oil is recirculated through line 56 into feeder case 14 as a flushing oil stream. In this way the feeder housing is swept free of any solids fines which may accumulate there together with solids fines separated from the product oil. Any oil remaining in the thickened sludge is quickly aporized and then the solids fines are rctorted rapidly because of their small size by the hot eduction gases at the to of the retorting kiln 10.

he fines-free product oil is removed from fines separator 34 through line. 56a and joins a minorstream of product oil separated from the. shale gas product of the 'retortiug operation. This gas is removed from manifold 30 through line 5.8 and is introduced into mist and entrainment separator, such as cyclone 60. Here the gas is freed of residual traces of oil product and the oil is produced through line 62 together with the larger portion of oil product removed from separator 34.

The oil-free retort gas is drawn from separator 60 by means of blower 64. This maintains the downward flow of ed ctiou gases through kiln 10 and disengaging zone 12 and maintains the lower portion of the retort under .a slightly subatmospheric pressure. A not production of hale gas is removed from the. blower discharge through line 66 at a rate of about 350 M s.c.f./d. (thousand standard cubic feet per day) controlled by valve 68 and pressure controller 70. The remaining quantity of shale gas is passed through line 72 for the generation of the hot retorting or cduction gas employed to contact the raw shale. I r

The recycle gas system consists essentially of recycle gas primary heater'74 and secondary heater 76'. A portion of the shale gas is introduced from line 72 through line 78 at a rate controlled byvvalve80 as fuel into prim rv heater 74.- This heater is provided with three in dividual coils, air heating coil 82, first recycle gas heating coil 84, and second recycle gas heating coil 86. A first portion of the recycle gas is introduced through line 88 at a rate controlled by valve 90 and passes through first recycle gas heatingcoilfi t, line 92, and is introduced as a preheated combustible gas into secondary heater 76. The preheated air removed from air preheating coil 82 passes through line 94 as the oxidizing agent into secondary heater 76. The preheating temperatures and the gas quantities are controlled so that a substantially inert (oxygemfreelfiue gas is produced from the secondary heater through line 96 at temperatures which between about l500 F.-and 2500 F. V

The second portion of recycle gas passes through line 98 at a rate controlled by valve '100 and is preheated in second recycle gas preheating coil 86. This preheated gas bypasses secondary heater 76 through line 102 at a rate controlled by valve 104. and pressure controller 106 which is actuated by and controls the pressure at. the top of the retort at a value substantially equal to atmospheric pressure. This bypass streamof recycle gas is combined in line-108 with the efiiuent from the secondary heater in such proportions as to produce an inert recycle eduction gas having a temperature within the range of from about 900 F. to about 1800 F., depending on the quantity of bypass flow. I l

This hot eduction gas recycle flows in sequence through fines retort zone 28, in which it contacts the shale fines concurrently, and through kiln in which it contacts the larger shale particles countercurrently and in which all of the product gases and vapors are cooled and condensed. Shale fines are introduced into fines retorting zone 28 through rotary air lock 26 or a similar sealing device. The fines have a large surface area per unit weight and the thickness of the particles is small so that heating and retorting occur rapidly. The spent shale fines are separated from the retort gas in dry fines separator- 110 and are discharged into ash hopper 112. The dry fines separator may be a cyclone separator or similar device. 1 i

The time of contact between the fines and the hot eduction gases in fines retorting zone 28 is preferably inversely proportional to the size of the fine particle. It depends upon the length of time between the point of contact at the outlet of rotary air lock 26 and dry fines separator 110. The time of contact is also dependent upon the slope of the fines retorting zone, which slope may range from about horizontal to and about 30 upward or downward from the horizontal, the line diameter, and the eduction gas velocity in the line. If an upward slope of greater than about 30 from the horizontal is employed, the larger fines move only at very low velocities or will actually stop unless very high gas velocities are used. Such velocities require excessively long fines retorting zones to maintain proper residence times for the larger fines, the smaller fines are treated for too long a time, and the zone is apt to plug with low velocity larger fines. If a downward slope of greater than about 30 from the horizontal is used, the gravitational effect on the larger fines becomes excessive and all the fine particles begin moving at, substantially the same velocity. The larger fines thus have an insutficient residence time unless excessively large retorting zone cross sections and relatively low gas-velocities are employed. At such low velocities, the smaller fines settle out and move at the same velocity as the larger fines. In either may range case of slopes greater than about 30 from the horizontal,

the inversely proportional relationship of residence time to particle size is lost. Thus slopes of less than 30 must be used in the fines retorting zone of this invention. In operation this contact time is varied by controlling the gas velocity in the fines retorting zone and the gas to fines ratio. The eduction gas velocity and the gas to fines ratio, or both, are controlled to maintain a condition of partial settling in the line. The larger fines particles drop to the lower surface of the fines retorting zone and travel more slowly than the main body of hot eduction gases containing the suspended smaller fines. This zone may be horizontal, or it may slope slightlyv upward or downward. The larger fine particles thereby obtain the longer contact time which is necessary for complete heating and retorting. The suspended fines-move along at substantially the same velocity as the eduction gas. With these techniques, complete retorting of all fines particles is readily accomplished.

The partially cooled eduction gases, containing oil gases and vapors produced in finesretorting, are removed from dry fines separator such as cyclone through line 114 at a rate controlled by valve 115 and are introduced directly into the top of eduction kiln 10. The hot eduction gases continue downwardly countercurrent to the upwardly moving fines-free shale. Here the fines-free shale is heated to retorting temperatures and additional hydrocarbon gases and vapors are retorted from this shale stream. This occurs in the upper onethird of kiln 10 approximately. The educted oils and gases pass downwardly countercurrent to the rising fresh shale preheating these solids and cooling and partially condensing the retort product in the lower two-thirds of kiln 10. This produces the cooled gas and condensed oils previously referred to which collectin manifold 30.

At the top of the kiln 10 spent shale ash accumulates and is discharged into ash hopper 112 by means of rotating scrapers, not shown, mounted in the top of hopper 112. It is in this atmosphere of hot shale ash and hot recycled eduction gases at the top of kiln 10 that the thickened sludge is introduced through line: 54. At the temperatures existing in the top of the kiln the oil present in the sludge is immediately vaporized and passes downwardly-with the eduction gases. The solids fines therein arerapidly retorted by the combined action of the hot ash and the hot eduction gases passing therethrough.

The ash from all the various sources discharges from ash hopper 112 through line, and is removed to suitable disposal facilities by means of ash conveyer 122. To prevent the uncontrolled entrance of air into the system, steam or other seal gas is introduced through line 124 at a rate controlled by valve 126 into the lower portion of ash hopper 112. A rotary air lock or equivalent devices may be used at the ash outlet to prevent or minimize air introduction.

In the manner described above every particle of' shale fed to the system'is retorted under conditions best suited to obtain the highest possible yield of oil and gas from that particle. The shale fines having mesh sizes of under about one-half inch are retorted concurrently with very hot gases under conditions in which the very' small fines have contactor residence times inthe fines retorting zone which are very much lower than the contact times provided for the larger solids fines. The main stream of fines-free shale" having a mesh size of about one-half inch and larger is contacted countercurrently with hot eduction gases under conditions controlled to retort completely the larger sized particles in the'shale feed; Because of.the full retorting ofall particles, the liquid yields obtained in the process of this invention approach 100% of Fischer Assay. r

In the present example. the product oil is produced at a rate of 18,610 gallons perday which is about 95% of Fischer Assay. The solids fines are kept out of the main body of the retort shale bed and the pressure difierential and accordingly the energy required to operate the process are both substantially reduced about 30%. The incoming bed of raw shale in the retort is employed to condense not only the oil vapors educ ted fromthe. larger sized shale stream but also to condense the oil vapors retorted from the fines. The API gravity of the product oil was 21.0. The retort gas was produced from the retort at av rateof.6.5 M s.c.-f. per ton of feed or about 4550 M s.c.f./d. The gross heating value. of this gas was about 100 B.t.u./s.c.f. The retorting rate at the retort is about 270. pounds per hour. per square foot. Air

is introducedinto the systemat a rate of 3.5 M s.c.f. per

ton of feed or 2450 M s.c.f./d. The rate of recycle gas flow through the fines retorting zone and the main retorting zone in series is about 24.01M s.c.f. per ton or 16,800 M s.c.fJd. The gas inlet temperature at'the top of kiln 10 is about 1300 F. The outlet temperature of the oil and gas from manifold zone 30 is about F. The spent shale ash is discharged from the system atabout 950 F.

. retorting zone.

l The primary advantages of'the above-described invention include the realization of very high burning rates and very high heating rates in the kiln, very high thermal efficiency due to the elimination of carbonate decomposition, the complete elimination of oxygen in the system which causes liquid product degradation, and the availability of the entire height of the retort for the heat transfer required to retort the solids and to cool and condense products. No structural height is necessary therefore to provide a separate zone for the burning of the spent shale. Also shale throughput is not limited by coke combustionrates and throughput can be more than doubled 'for a given retort size. The required retort height is thus reduced for .a given shale feed rate, or the shale capacity of a given retort is correspondingly increased. Plowing of the shale is unnecessary and the heavy equipment needed to efiect such plowing and the high power requirements are thus eliminated. Thermal 8 temperature between about 1500 F. and about 2500 F., and is combined with a sufiicient amount of said preheated second recycle stream to produce said secondary hot eduction gas with a temperature between about 900 F. and, about 1800 F. and substantially free'of oxygen. 5. A process according to claim 1 in combination with the step of controlling the velocity of said secondary hot eduction gas during the concurrent contact of said fines efiiciency is substantially increased as compared to other types of gas fired retorts through a reduction in maximum operating temperature to one at which only a minor proportion of the naturally occurring carbonates'are decomposed.

A particular embodiment of the present invention has been hereinabove described in considerable detail by way of illustration. It should be understood that various other modifications and adaptations thereof may be made by those skilled in this particular art without departing from the spirit and scope of this invention as set forth in the appended claims.

I claim:

l. Aprocess for treating hydrocarbon-containing and hydrocarbon-producing solids of different particle size which comprises separating said solids into a fines portion and a coarse portion; passing said coarse portion upwardly in the form of a dense bed from a solids feeder zone successively through a disengaging zone, a solids preheating and product cooling zone, and a retorting zone; passing a primary stream of hot eduction gas downwardly through said retorting zone to educt hydrocarbons from said coarse portion; cooling and partially condensing said hydrocarbons in said solids preheating and product condensing zone; removing the liquid and gas phases from said disengaging zone; separating said liquid and gas 7 phases from each other; burning part of said separated gas as fuel in a primary heating zone; preheating a first and a second recycle stream of said gas and a stream of oxygen-containing gas in 'said primary heating zone; burning the preheated first recycle stream with the preheated oxygen-containing gas in a secondary heating zone to form'a hot flue gas; combining said hot flue gas with the preheated second recycle stream to form a secondary hot eduction gas; concurrently contacting said fines portion with saidsecondary hot eduction gas in a fines educ-' tion zone isolated from said retorting zone, thereby educting hydrocarbons from said fines; separating spent fines from, the hot gaseous efiiuent'of .said fines eduction zone; passing the hot fines-free gaseous effluent into the top of said retorting zone as said primary hot eduction gas to contact said coarser portion thereincountercurr'ently; and removing spent solids. from the top of said '2. A process according to claim 1 in combination with the step of separating solids fines from the separated liquid phase and retorting the separated fines by contacting them with said primary hot eduction gas at the top of the rising bed of said coarse portion in said, re-

torting zone.

3. Aprocess according to claim 2 in combination with the steps of flushing a stream of product oil through said solids feeder zone. to sweep solids fines therefrom and retorting said lines with those separated from the liquid product.

4. A process according to claim 1 wherein said hot flue gas is produced from said secondary heating zone at a current contact is effected in an elongated fines retorting zone having a slope in the flow direction ranging from about 30 downward from the horizontal to about 30 upward from the horizontal.

7. A process according to claim ,I- wherein said fines portion has an average mesh size of about 0.5 inch and smaller. 7

8. A process according to claim 1 wherein said solids comprise oil'shale. r

9. In a process for retorting oil shale of different particle size to produce shale oil and gas wherein said oil shale is passed upwardly as a dense bed successively through a fluid disengaging zone and a retorting zone countercurrent to an eduction gas flow at temperatures sufiicient to educt shale oil and gas'from said shale, and wherein said shale gas is separated from said shale oil and is recirculated at least in partas said eduction gas, the improvement which comprises separating the oil shale fines from the raw shale feed; passing the substantially fines-free stream upwardly through said disengaging and retorting zones; concurrently contacting the shale fines in a fines retorting zone isolated from said retorting zone with said eduction gas to produce spent shale fines; controlling the temperature of said eduction gas at from about 900 F. to about'l,800 F. at the entrance to said fin-es retorting zone; and then passing said eduction gas cross section, and the eduction gas'velocity and the gasto-fines ratio in said zone are controlled to maintain the smaller fines suspendedin and moving at substantially the eduction gas velocity therein and to maintain the larger fines in a condition of hindered settling and moving along the lower surface of said fines retorting zone at a-velocity substantially below that of said eduction gas, whereby the residence time of each particle in said zone is substantially inversely proportional to its mesh size.

11. A process according to claim 10 wherein the elongated shale fines retorting zone is inclined at a slope of not more than about 30 from the horizontal.

12. A process for retorting shale which comprises passing granular shale upwardly in the form of a dense bed from a solids feeder zone successively through a product disengaging zone and a retorting zone; passing a sufiicient amount of an essentially oxygen-free eduction gas at a temperature of from about 900 F. to about 1,800 F. downwardly through said retorting zone to educt hydrocarbons from said shale; withdrawing liquid hydrocarbons admixed with shale fines from said dissizes up to about six inches in diameter into a fines fraction consisting essentially of particles having a diameter of not more than about one-half inch and a coarse fraction consisting essentially of particles of larger diameter; producing a secondary eduction gas having a temperature of about 900 F. to about 1,800 E; contacting said fines fraction with said secondary eduction gas to produce a primary eduction gas containing hydrocarbons educted from said fines fraction; and contacting said coarse fraction with said primary eduction gas so as to educt additional hydrocarbons therefrom.

14. A process for retorting shale which comprises passing granular shale upwardly in the form of a dense bed from a solids feeder zone successively through a product disengaging zone and a retorting zone; passing a suflicient amount of an essentially oxygen-free eduction gas at a temperature of from about 900 F. to about 1,800 F. downwardly through said retorting zone to educt hydrocarbons from said shale; withdrawing liquid hydrocarbons admixed with shale fines from said disengaging zone; and introducing said shale fines into the top of said retorting zone whereby said shale fines are contacted with said eduction gas; and removing spent shale from the top of said eduction zone.

15. A process for retorting shale which comprises passing granular shale upwardly in the form of a dense bed from a solids feeder zone successively through a product disengaging zone and a retorting zone; passing a sutlicient amount of an essentially oxygen-free eduction gas at a temperature of from about 900 F. to about 1,800 F. downwardly through said retorting zone to educt hydrocarbons from said shale; withdrawing liquid hydrocarbons and shale fines from said feeder zone, and introducing said shale fines into the top of said retorting zone whereby said shale fines are contacted with said eduction gas; and removing spent shale from the top of said eduction zone.

References Cited in the file of this patent UNITED STATES PATENTS 1,906,755 Kai-rick May 2, 1933 2,131,702 Berry Sept. 27, 1938 2,501,153 Berg Mar. 21, 1950 2,614,069 Matheson Oct. 14, 1952 2,738,315 Martin et a1. Mar. 13, 1956 2,875,137 Lietfers et a1. Feb. 24, 1959 2,892,758 Hotz et al. June 30, 1959 

1. A PROCESS FOR TREATING HYDROCARBON-CONTAINING AND HYDROCARBON-PRODUCING SOLIDS OF DIFFERENT PARTICLE SIZE WHICH COMPRISES SEPARATING SAID SOLIDS INTO A FINES PORTION AND A COARSE PORTION, PASSING SAID COARSE PORTION UPWARDLY IN THE FORM OF A DENSE BED FROM A SOLIDS FEEDER ZONE SUCCESSIVELY THROUGH A DISENGAGING ZONE, A SOLIDS PREHEATING AND PRODUCT COOLING ZONE, AND A RETORTING ZONE, PASSING A PRIMARY STREAM OF HOT EDUCTION GAS DOWNWARDLY THROUGH SAID RETORTING ZONE TO EDUCT HYDROCARBONS, FROM SAID COARSE PORTION, COOLING AND PARTIALLY CONDENSING SAID HYDROCARBONS IN SAID SOLIDS PREHEATING AND PRODUCT CONDENSING ZONE, REMOVING THE LIQUID AND GAS PHASES FROM SAID DISENGAGING ZONE, SEPARATING SAID LIQUID AND GAS PHASES FROM EACH OTHER, BURNING PART OF SAID SEPARATED GAS AS FUEL IN A PRIMARY HEATING ZONE, PREHEATING A FIRST AND A SECOND RECYCLE STREAM OF SAID GAS AND A STREAM OF OXYGEN-CONTAINING GAS IN SAID PRIMARY HEATING ZONE, BURNING THE PREHEATED FIRST RECYCLE STREAM WITH THE PREHEATED OXYGEN-CONTAINING GAS IN A SECONDARY HEATING ZONE TO FORM A HOT FLUE GAS, COMBINING SAID HOT FLUE GAS WITH THE PREHEATED SECOND RECYCLE STREAM TO FORM A SECONDARY HOT EDUCTION GAS, CONCURENTLY CONTACTING SAID FINES PORTION WITH SAID SECONDARY HOT EDUCTION GAS IN A FINERS EDUCTION ZONE ISOLATED FROM SAID RETORTING ZONE, THEREBY EDUCTING HYDROCARBONS FROM SAID FINES, SEPARATING SPENT FINES FROM THE HOT GASEOUS EFFLUENT OF SAID FINES EDUCTION ZONE, PASSING THE HOT FINES-FREE GASEOUS EFFLUENT INTO THE TOP OF SAID RETORTING ZONE AS SAID PARIMARY HOT EDUCTION GAS TO CONTACT SAID COARSER PORTION THEREIN COUNTERCURRENTLY, AND REMOVING SPENT SOLIDS FROM THE TOP OF SAID RETORTING ZONE. 